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January 26-27 Snowstorm Disco VI


ConvectiveSolutions

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Scott what I respect the most about you is your outright honesty even if it flies in the face of weenieism. Maybe I didn't pay attention in the past, but this year you seem to really lay it out there in all directions, all options and if something tosses a red flag in your mind even if it's small you throw it out there. I appreciate that, I know everyone else does too. It's pretty rare, and I have a ton of respect for you for doing it.

Eh, not that worried about it either way my friend. If you look at the high res twister maps, it's got the micro low coming onshore of west florida...yeah I know it's a convective complex....it kind of plays with that and I think they really disrupt it's surface low presentation. BUT, I don't think there's any doubt the mid/high level moisture will initially miss us SE as Bouchard said. Then we have to wait for the low to wrap up. This may be where the NAM is falling down, not developing that low enough, but again, two stage storm on these models and the first stage whiffs.

If you follow the NAM through there's three things going on:

1st: The feature that is now on the coast driving all the convection comes up and misses WIDE right. GFS/NAM/RGEM/GGEM et all...show this IMO. I think this is maybe a lock, will be a lock post rest of suite.

2nd. The feature in the eastern GOM, rides NNE into the SE US. THIS starts to develop as it continues to move NE, the moisture expands as it comes across NC. Spin it through at 700, this feature ends up being rolled into the developing comma head.

3rd. M/L main moves across draws in #2, this is the entirety of the NAM solution, 3 moving parts.

No comment on accuracy, if it's falling down it's with part 2.

Thanks for the nice words Scott. I don't like seeing it, but I think it's lovin' the convection too much. So called convective feedback is real to some extent, but I think the NAM is going nuts with it and forcing the low to scoot ene a lot more than it should. My guess is the GFS is as good or even a little better than 18z. Who knows, maybe it goes se, but given all the other guidance...me thinks the NAM is suspect.

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Whole lotta low level moisture down on the South Coast tonight. Westerly and Newport are both reporting freezing fog with temps of 16 and 19. But I gotta wonder who's manning these reporting stations....because both are reporting visibilities of a quarter mile and it's not that low where I'm at

LOL ASOS, means Automatic

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Doh!

I am laughing my azz off right now as Matt is tearing the NAM a new one. :lmao:

"Yeah NAM, it's going to be a flat wave"

If he'd take a second and read the NCEP status message maybe he'd chill out. With the 1/25/00 event one of the key things Brian caught that day was a missing RAOB in I think Texas or New Orleans right at a key time. I remember we were hammering the big dog solution and a run came in that didn't do what we thought...and sure enough that was the problem. It probably made a difference tonight, especially with th later wrap up. IMO, I actually suspect it could be a big part of the problem pending the rest of the suite...and if it is the status message has been up since 835pm...well....

I

Thanks for the nice words Scott. I don't like seeing it, but I think it's lovin' the convection too much. So called convective feedback is real to some extent, but I think the NAM is going nuts with it and forcing the low to scoot ene a lot more than it should. My guess is the GFS is as good or even a little better than 18z. Who knows, maybe it goes se, but given all the other guidance...me thinks the NAM is suspect.

Yep, I'm not reacting much either way. Can see why it's doing it....can also see why it could easily be wrong without the baloon down in Tampa. Two failed obs in critical areas...ugh.

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If he'd take a second and read the NCEP status message maybe he'd chill out. With the 1/25/00 event one of the key things Brian caught that day was a missing RAOB in I think Texas or New Orleans right at a key time. I remember we were hammering the big dog solution and a run came in that didn't do what we thought...and sure enough that was the problem. It probably made a difference tonight, especially with th later wrap up. IMO, I actually suspect it could be a big part of the problem pending the rest of the suite...and if it is the status message has been up since 835pm...well....

Yep, I'm not reacting much either way. Can see why it's doing it....can also see why it could easily be wrong without the baloon down in Tampa. Two failed obs in critical areas...ugh.

He's well aware of the status message.

IIt's boiling down to the NAM blowing up the SLP on that piece of vorticity offshore.

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This from PHI AFD at 9:00

BASED ON THE 00Z SOUNDINGS AND SURFACE OBSERVATIONS, PCPN ITSELF IS

LAGGING THE FASTER MODEL SOLUTIONS, LEANING TOWARD A ECMWF AND

WRF-NMM COMPROMISE VERIFYING THE BEST AS OF 00Z. THE 18Z GFS .01

ISOHYET WAS ABOUT 75 MILES TOO FAR TO THE NORTH, ITS 0.10 ISOHYET

WAS VERIFYING BETTER FOR THE START OF THE MEASURABLE.

WE ALSO SUSPECTED THE GULF COAST CONVECTION WOULD CAUSE SOME

MODELING PROBLEMS AND THE SFC LOW VERIFIED MUCH FARTHER NORTH (IN

ALABAMA) THAN MOST OF THE MODELS HAD, CAN GGEM AND ECMWF VERIFYING

THE BEST THERE.

AS FOR THE 500MB PATTERN, THE TROF IS NOT AS SHARP AS MODELED,

ESPECIALLY ON THE EASTERN FLANK WHERE HEIGHTS ARE 10-20M LOWER.

THE RIDGING THEN TOWARD US WAS PRETTY CLOSE. THE POSITIONING OF

THE CLOSED LOW WAS SPOT ON.

THE 850MB AND 925MB TEMP 12HR FORECASTS ARE VERIFYING ABOUT HALF A

DEGREE TO DEGREE CELSIUS TOO LOW, WITH THE NAM HAVING THE LION'S

SHARE OF THE COLD ERRORS. ECMWF WAS CLOSEST.

IN THE SHORTER TERM, GIVEN THE LAG, WE SLOWED THE ARRIVAL OF PCPN

DOWN FOR THE OVERNIGHT. THE LATEST GFS FORECAST SOUNDINGS SUGGEST

MORE OF A SNOW OR SLEET TO RAIN PTYPE AT THE ONSET OF THE

PRECIPITATION IN THE SOUTHEASTERN PART OF OUR CWA WITH LESS OF A

FREEZING RAIN THREAT. TEMPS HAVE DROPPED WITH THE THINNER CLOUDS

THIS EVENING AND WE'LL HAVE TO SEE IF THEY RESPOND BACK UPWARD

ONCE THE CLOUDS THICKEN.

AS FOR THE REST OF THE FORECAST THE WEAKER TROF MAY BE ABLE TO

COMPENSATE FOR THE NORTHERN DISPLACEMENT OF THE LOW AS THE TURN WE

WOULD INFER WOULD BE MORE GRADUAL. THE THERMAL FIELD VERIFYING

SLIGHTLY WARMER WILL GIVE US PAUSE TO SEE IF THE 00Z MODEL SUITE

CHANGES MUCH IN MAKING THE FINAL ADVISORY/WARNING DECISION.

&&

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Great information thanks for sharing. I think one of the most critical parts is what they said about the trough not being as sharp..and that the turn may be more gradual compensating for northward displacement.

I'm wondering about the surface low placement comment....even the 18z NAM had it over the Panhandle/extending into AL which is essentially what this shows from the SPC http://w1.spc.woc.noaa.gov/exper/mesoanalysis/new/archiveviewer.php?sector=18&parm=pmsl

This from PHI AFD at 9:00

BASED ON THE 00Z SOUNDINGS AND SURFACE OBSERVATIONS, PCPN ITSELF IS

LAGGING THE FASTER MODEL SOLUTIONS, LEANING TOWARD A ECMWF AND

WRF-NMM COMPROMISE VERIFYING THE BEST AS OF 00Z. THE 18Z GFS .01

ISOHYET WAS ABOUT 75 MILES TOO FAR TO THE NORTH, ITS 0.10 ISOHYET

WAS VERIFYING BETTER FOR THE START OF THE MEASURABLE.

WE ALSO SUSPECTED THE GULF COAST CONVECTION WOULD CAUSE SOME

MODELING PROBLEMS AND THE SFC LOW VERIFIED MUCH FARTHER NORTH (IN

ALABAMA) THAN MOST OF THE MODELS HAD, CAN GGEM AND ECMWF VERIFYING

THE BEST THERE.

AS FOR THE 500MB PATTERN, THE TROF IS NOT AS SHARP AS MODELED,

ESPECIALLY ON THE EASTERN FLANK WHERE HEIGHTS ARE 10-20M LOWER.

THE RIDGING THEN TOWARD US WAS PRETTY CLOSE. THE POSITIONING OF

THE CLOSED LOW WAS SPOT ON.

THE 850MB AND 925MB TEMP 12HR FORECASTS ARE VERIFYING ABOUT HALF A

DEGREE TO DEGREE CELSIUS TOO LOW, WITH THE NAM HAVING THE LION'S

SHARE OF THE COLD ERRORS. ECMWF WAS CLOSEST.

IN THE SHORTER TERM, GIVEN THE LAG, WE SLOWED THE ARRIVAL OF PCPN

DOWN FOR THE OVERNIGHT. THE LATEST GFS FORECAST SOUNDINGS SUGGEST

MORE OF A SNOW OR SLEET TO RAIN PTYPE AT THE ONSET OF THE

PRECIPITATION IN THE SOUTHEASTERN PART OF OUR CWA WITH LESS OF A

FREEZING RAIN THREAT. TEMPS HAVE DROPPED WITH THE THINNER CLOUDS

THIS EVENING AND WE'LL HAVE TO SEE IF THEY RESPOND BACK UPWARD

ONCE THE CLOUDS THICKEN.

AS FOR THE REST OF THE FORECAST THE WEAKER TROF MAY BE ABLE TO

COMPENSATE FOR THE NORTHERN DISPLACEMENT OF THE LOW AS THE TURN WE

WOULD INFER WOULD BE MORE GRADUAL. THE THERMAL FIELD VERIFYING

SLIGHTLY WARMER WILL GIVE US PAUSE TO SEE IF THE 00Z MODEL SUITE

CHANGES MUCH IN MAKING THE FINAL ADVISORY/WARNING DECISION.

&&

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LOL ASOS, means Automatic

Don't be a smarta$$. How can can automated stations determine visibility? Because the Newport reporting station located in Middletown was reporting a .25 mile visibility and it was at least a couple miles.....What about the major airports? Is there a person reporting the visibility? There are automated reporting stations in our area like Montauk. BID and Provincetown and the visibility doesn't seem to be measured at these stations.

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Don't be a smarta$$. How can can automated stations determine visibility? Because the Newport reporting station located in Middletown was reporting a .25 mile visibility and it was at least a couple miles.....What about the major airports? Is there a person reporting the visibility? There are automated reporting stations in our area like Montauk. BID and Provincetown and the visibility doesn't seem to be measured at these stations.

snowman21's asos fetish alarm just went off...he will be here in a few minutes to help explain asos and awos to you.

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Don't be a smarta$. How can can automated stations determine visibility? Because the Newport reporting station located in Middletown was reporting a .25 mile visibility and it was at least a couple miles.....What about the major airports? Is there a person reporting the visibility? There are automated reporting stations in our area like Montauk. BID and Provincetown and the visibility doesn't seem to be measured at these stations.

They have sensors.

http://www.nws.noaa....dfs/aum-toc.pdf

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Keep in mind that was based on 00z obs but not based on the 00z model run

So correct me if I'm wrong because I don't use ewall, but it's a big miss for most?

And at the same time what Leesun just posted from Philly says they are going for a compromise of the WRF NMM and Euro?

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